Lubricated axially-cylindrical journals and their bearings are well-known and widely used. In such devices, an axially-cylindrical shaft, called the journal, is positioned within a mating cylindrical journal bearing. When the journal is at rest, its weight allows line contact of the shaft and bearing. In use, between the shaft and bearing, a film of oil lubricates the device, typically so that with speed increase full-film or full hydrodynamic lubrication is generated as a consequence of the interaction of the viscosity of the oil, the speed of the journal, and the load applied normal to the journal. This interaction enables the device to rotate at lessened levels of friction as a consequence of what is technically called `hydrodynamic lubrication`. Thus, engines run smoothly with only minor amounts of wear since the journal and bearing do not touch directly but are separated by the lubricant. See e.g., Obert, "Internal Combustion Engines and Air Pollution," Harper & Row Publishers, New York (1973) at pages 633-6.
One limitation in such devices, however, is the weight the journal will support. To carry a large load as, for example, in crankshafts and camshafts of larger engines, the length of the cylindrical journal in general registry with its accompanying bearing must be substantial. Accordingly, much more weight and engine length is necessitated.
It would be desirable to have lighter engines and motors so that more power can be transformed into external work, and so that mobility in general might be enhanced.